diff --git a/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata b/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
index 1d526a1..919434a 100644
--- a/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
+++ b/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
@@ -2,6 +2,6 @@
 <Workspace
    version = "1.0">
    <FileRef
-      location = "group:Runner.xcodeproj">
+      location = "self:">
    </FileRef>
 </Workspace>
diff --git a/example/lib/main.dart b/example/lib/main.dart
index c6546be..c86f9c6 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -105,7 +105,7 @@ class _CustomInfiniteList extends StatelessWidget {
           },
         ),
         onError: (context, retry, error) {
-          Scaffold.of(context)
+          ScaffoldMessenger.of(context)
             ..hideCurrentSnackBar()
             ..showSnackBar(SnackBar(
               content: Text(error.toString()),
@@ -119,7 +119,7 @@ class _CustomInfiniteList extends StatelessWidget {
   }
 }
 
-Future<List<String>> _itemLoader(int limit, {int start = 0}) async {
+Future<List<String>?> _itemLoader(int limit, {int start = 0}) async {
   await Future<void>.delayed(const Duration(seconds: 1));
   if (start >= 100) return null;
   if (Random().nextInt(2) == 0) throw Exception('Oops!');
@@ -136,9 +136,9 @@ class _Loading extends StatelessWidget {
 
 class _Error extends StatelessWidget {
   const _Error({
-    Key key,
-    this.error,
-    this.retry,
+    Key? key,
+    required this.error,
+    required this.retry,
   }) : super(key: key);
 
   final Object error;
@@ -153,7 +153,7 @@ class _Error extends StatelessWidget {
         children: [
           Text(
             error.toString(),
-            style: theme.textTheme.headline4.copyWith(color: theme.errorColor),
+            style: theme.textTheme.headline4?.copyWith(color: theme.errorColor),
             textAlign: TextAlign.center,
           ),
           const SizedBox(height: 16),
@@ -169,7 +169,7 @@ class _Error extends StatelessWidget {
 }
 
 class _ErrorLoader extends StatelessWidget {
-  const _ErrorLoader({Key key, @required this.retry}) : super(key: key);
+  const _ErrorLoader({Key? key, required this.retry}) : super(key: key);
   final VoidCallback retry;
 
   @override
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 419028c..52b9165 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -5,7 +5,7 @@ publish_to: none
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
@@ -14,7 +14,7 @@ dependencies:
     path: ../
 
 dev_dependencies:
-  very_good_analysis: ^1.0.4
+  very_good_analysis: ^2.0.0
 
 flutter:
   uses-material-design: true
diff --git a/lib/very_good_infinite_list.dart b/lib/very_good_infinite_list.dart
index d34c7b5..9e7cdbc 100644
--- a/lib/very_good_infinite_list.dart
+++ b/lib/very_good_infinite_list.dart
@@ -19,7 +19,7 @@ class InfiniteListException implements Exception {}
 ///
 /// * [limit] is the number of items you'd like to fetch.
 /// * [start] is an optional offset which defaults to 0.
-typedef ItemLoader<T> = Future<List<T>> Function(int limit, {int start});
+typedef ItemLoader<T> = Future<List<T>?> Function(int limit, {int start});
 
 /// Function which returns a [Widget] given a [context], [retry], and [error].
 /// Used by [InfiniteList] to render widgets in response to exceptions thrown
@@ -48,15 +48,15 @@ typedef OnError = void Function(
 class InfiniteListBuilder<T> {
   /// {@macro infinite_list_builder}
   const InfiniteListBuilder({
-    @required this.success,
-    WidgetBuilder loading,
-    ErrorBuilder error,
-    WidgetBuilder empty,
+    required this.success,
+    WidgetBuilder? loading,
+    ErrorBuilder? error,
+    WidgetBuilder? empty,
   })  : _loading = loading,
         _error = error,
         _empty = empty;
 
-  final WidgetBuilder _loading;
+  final WidgetBuilder? _loading;
 
   /// [WidgetBuilder] which is invoked when the [InfiniteList]
   /// is rendered while content is being fetched by the [ItemLoader].
@@ -73,7 +73,7 @@ class InfiniteListBuilder<T> {
   /// retrieved from the [ItemLoader].
   final Widget Function(BuildContext, T) success;
 
-  final ErrorBuilder _error;
+  final ErrorBuilder? _error;
 
   /// [WidgetBuilder] which is invoked when the [InfiniteList]
   /// is rendered and an [InfiniteListException]
@@ -89,7 +89,7 @@ class InfiniteListBuilder<T> {
         };
   }
 
-  final WidgetBuilder _empty;
+  final WidgetBuilder? _empty;
 
   /// [WidgetBuilder] which is invoked when the [InfiniteList]
   /// is rendered and the [ItemLoader] has returned an empty list.
@@ -109,20 +109,18 @@ class InfiniteListBuilder<T> {
 class InfiniteList<T> extends StatefulWidget {
   /// {@macro infinite_list}
   const InfiniteList({
-    Key key,
-    @required this.itemLoader,
-    @required this.builder,
-    WidgetBuilder bottomLoader,
-    ErrorBuilder errorLoader,
+    Key? key,
+    required this.itemLoader,
+    required this.builder,
+    WidgetBuilder? bottomLoader,
+    ErrorBuilder? errorLoader,
+    ScrollController? scrollController,
     this.debounceDuration,
     this.reverse = false,
     this.onError,
     this.padding,
-    ScrollController scrollController,
-    double scrollOffsetThreshold,
-  })  : assert(itemLoader != null),
-        assert(builder != null),
-        _bottomLoader = bottomLoader,
+    double? scrollOffsetThreshold,
+  })  : _bottomLoader = bottomLoader,
         _errorLoader = errorLoader,
         _scrollController = scrollController,
         _scrollOffsetThreshold =
@@ -130,7 +128,7 @@ class InfiniteList<T> extends StatefulWidget {
         super(key: key);
 
   /// The amount of space by which to inset the children of the [builder].
-  final EdgeInsetsGeometry padding;
+  final EdgeInsetsGeometry? padding;
 
   /// {@macro infinite_list_builder}
   final InfiniteListBuilder<T> builder;
@@ -139,7 +137,7 @@ class InfiniteList<T> extends StatefulWidget {
   /// to lazily fetch content.
   final ItemLoader<T> itemLoader;
 
-  final WidgetBuilder _bottomLoader;
+  final WidgetBuilder? _bottomLoader;
 
   /// [WidgetBuilder] which is responsible for rendering the bottom loader
   /// widget which is rendered when the user scrolls to the bottom of the list
@@ -152,7 +150,7 @@ class InfiniteList<T> extends StatefulWidget {
             );
   }
 
-  final ErrorBuilder _errorLoader;
+  final ErrorBuilder? _errorLoader;
 
   /// [WidgetBuilder] which is responsible for rendering the bottom loader
   /// widget which is rendered when additional content is unable to be loaded
@@ -167,13 +165,13 @@ class InfiniteList<T> extends StatefulWidget {
           );
 
   /// {@macro on_error}
-  final OnError onError;
+  final OnError? onError;
 
-  final ScrollController _scrollController;
+  final ScrollController? _scrollController;
 
   /// Debounce duration for the [itemLoader].
   /// Defaults to `const Duration(milliseconds: 100)`.
-  final Duration debounceDuration;
+  final Duration? debounceDuration;
 
   /// Whether the scroll view scrolls in the reading direction.
   ///
@@ -196,9 +194,9 @@ class InfiniteList<T> extends StatefulWidget {
 }
 
 class _InfiniteListState<T> extends State<InfiniteList<T>> {
-  ScrollController _scrollController;
-  _ListController<T> _controller;
-  _Debouncer _debouncer;
+  late ScrollController _scrollController;
+  late _ListController<T> _controller;
+  late _Debouncer _debouncer;
 
   void _onListStateChanged() {
     final state = _controller.value;
@@ -225,7 +223,7 @@ class _InfiniteListState<T> extends State<InfiniteList<T>> {
 
   @override
   void dispose() {
-    _debouncer?.dispose();
+    _debouncer.dispose();
     _controller
       ..removeListener(_onListStateChanged)
       ..dispose();
@@ -250,7 +248,7 @@ class _InfiniteListState<T> extends State<InfiniteList<T>> {
   Widget build(BuildContext context) {
     return ValueListenableBuilder(
       valueListenable: _controller,
-      builder: (context, state, child) {
+      builder: (context, _ListState<T> state, child) {
         final itemCount = state.hasReachedMax == false
             ? state.items.length + 1
             : state.items.length;
@@ -314,9 +312,9 @@ class _InfiniteListState<T> extends State<InfiniteList<T>> {
 
 class _DefaultError extends StatelessWidget {
   const _DefaultError({
-    Key key,
-    this.error,
-    this.retry,
+    Key? key,
+    required this.error,
+    required this.retry,
   }) : super(key: key);
 
   final Object error;
@@ -331,7 +329,7 @@ class _DefaultError extends StatelessWidget {
         children: [
           Text(
             '$error',
-            style: theme.textTheme.headline4.copyWith(color: theme.errorColor),
+            style: theme.textTheme.headline4?.copyWith(color: theme.errorColor),
             textAlign: TextAlign.center,
           ),
           const SizedBox(height: 16),
@@ -346,7 +344,7 @@ class _DefaultError extends StatelessWidget {
 }
 
 class _DefaultErrorLoader extends StatelessWidget {
-  const _DefaultErrorLoader({Key key, @required this.retry}) : super(key: key);
+  const _DefaultErrorLoader({Key? key, required this.retry}) : super(key: key);
   final VoidCallback retry;
 
   @override
@@ -368,7 +366,7 @@ class _ListException implements Exception {
 
   final Object value;
 
-  static const none = _ListException(null);
+  static const none = _ListException(Object());
 }
 
 class _ListState<T> {
@@ -387,11 +385,11 @@ class _ListState<T> {
   final _ListException exception;
 
   _ListState<T> copyWith({
-    @required _ListStatus status,
-    int currentIndex,
-    List<T> items,
-    bool hasReachedMax,
-    _ListException exception,
+    required _ListStatus status,
+    int? currentIndex,
+    List<T>? items,
+    bool? hasReachedMax,
+    _ListException? exception,
   }) {
     return _ListState<T>(
       currentIndex: currentIndex ?? this.currentIndex,
@@ -455,10 +453,10 @@ class _ListController<T> extends ValueNotifier<_ListState<T>> {
 }
 
 class _Debouncer {
-  _Debouncer({Duration delay}) : _delay = delay ?? _kDebounceDuration;
+  _Debouncer({Duration? delay}) : _delay = delay ?? _kDebounceDuration;
 
   final Duration _delay;
-  Timer _timer;
+  Timer? _timer;
 
   void call(void Function() action) {
     _timer?.cancel();
diff --git a/pubspec.yaml b/pubspec.yaml
index b9ee70c..59e6563 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,15 +2,15 @@ name: very_good_infinite_list
 description: >-
   A Very Good Infinite List Widget created by Very Good Ventures.
   Comes in handy when making activity feeds, news feeds, etc.
-version: 0.2.1
+version: 0.3.0
 repository: https://github.com/VeryGoodOpenSource/very_good_infinite_list
 issue_tracker: https://github.com/VeryGoodOpenSource/very_good_infinite_list/issues
 homepage: https://github.com/VeryGoodOpenSource/very_good_infinite_list
 documentation: https://github.com/VeryGoodOpenSource/very_good_infinite_list
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
-  flutter: ">=1.17.0"
+  sdk: ">=2.12.0 <3.0.0"
+  flutter: ">=2.0.0"
 
 dependencies:
   flutter:
@@ -19,4 +19,4 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  very_good_analysis: ^1.0.4
+  very_good_analysis: ^2.0.0
diff --git a/test/very_good_infinite_list_test.dart b/test/very_good_infinite_list_test.dart
index 0b13ffa..5d60db9 100644
--- a/test/very_good_infinite_list_test.dart
+++ b/test/very_good_infinite_list_test.dart
@@ -4,31 +4,9 @@ import 'package:very_good_infinite_list/very_good_infinite_list.dart';
 
 void main() {
   group('InfiniteList', () {
-    group('constructor', () {
-      test('throws AssertionError when itemLoader is null', () {
-        expect(
-          () => InfiniteList(
-            itemLoader: null,
-            builder: InfiniteListBuilder(success: (_, __) => const SizedBox()),
-          ),
-          throwsAssertionError,
-        );
-      });
-
-      test('throws AssertionError when builder is null', () {
-        expect(
-          () => InfiniteList(
-            itemLoader: (int limit, {int start}) async => [],
-            builder: null,
-          ),
-          throwsAssertionError,
-        );
-      });
-    });
-
     testWidgets('updates scroll controller when changed', (tester) async {
       var itemLoaderCallCount = 0;
-      final itemLoader = (int limit, {int start}) async {
+      final itemLoader = (int limit, {int? start}) async {
         itemLoaderCallCount++;
         return List.generate(15, (i) => i);
       };
@@ -91,7 +69,7 @@ void main() {
     });
 
     testWidgets('reverse updates list view', (tester) async {
-      final itemLoader = (int limit, {int start}) async {
+      final itemLoader = (int limit, {int? start}) async {
         return List.generate(15, (i) => i);
       };
 
@@ -110,7 +88,7 @@ void main() {
     });
 
     testWidgets('list view is not reversed by default', (tester) async {
-      final itemLoader = (int limit, {int start}) async {
+      final itemLoader = (int limit, {int? start}) async {
         return List.generate(15, (i) => i);
       };
 
@@ -128,7 +106,7 @@ void main() {
     });
 
     testWidgets('list view supports custom padding', (tester) async {
-      final itemLoader = (int limit, {int start}) async {
+      final itemLoader = (int limit, {int? start}) async {
         return List.generate(15, (i) => i);
       };
       const padding = EdgeInsets.all(16);
@@ -148,7 +126,7 @@ void main() {
 
     testWidgets('invokes itemLoader immediately', (tester) async {
       var itemLoaderCallCount = 0;
-      final itemLoader = (int limit, {int start}) {
+      final itemLoader = (int limit, {int? start}) async {
         itemLoaderCallCount++;
       };
 
@@ -162,7 +140,7 @@ void main() {
 
     testWidgets('renders default loading widget by default', (tester) async {
       await tester.pumpApp(InfiniteList(
-        itemLoader: (int limit, {int start}) async => [],
+        itemLoader: (int limit, {int? start}) async => [],
         builder: InfiniteListBuilder(success: (_, __) => const SizedBox()),
       ));
 
@@ -172,7 +150,7 @@ void main() {
     testWidgets('renders default bottom loader widget by default',
         (tester) async {
       await tester.pumpApp(InfiniteList(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           return List.generate(1, (i) => i);
         },
         builder: InfiniteListBuilder(success: (_, __) => const SizedBox()),
@@ -190,15 +168,15 @@ void main() {
         (tester) async {
       var itemLoaderCallCount = 0;
       final itemLoaderResults = [
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           return List.generate(15, (i) => i);
         },
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           throw Exception('oops');
         },
       ];
       await tester.pumpApp(InfiniteList<int>(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           itemLoaderCallCount++;
           return itemLoaderResults.removeAt(0).call(limit, start: start);
         },
@@ -240,15 +218,15 @@ void main() {
     testWidgets('renders default error widget by default', (tester) async {
       var itemLoaderCallCount = 0;
       final itemLoaderResults = [
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           return List.generate(15, (i) => i);
         },
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           throw InfiniteListException();
         },
       ];
       await tester.pumpApp(InfiniteList<int>(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           itemLoaderCallCount++;
           return itemLoaderResults.removeAt(0).call(limit, start: start);
         },
@@ -290,15 +268,15 @@ void main() {
     testWidgets('retry from first time failure', (tester) async {
       var itemLoaderCallCount = 0;
       final itemLoaderResults = [
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           throw InfiniteListException();
         },
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           return List.generate(15, (i) => i);
         },
       ];
       await tester.pumpApp(InfiniteList<int>(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           itemLoaderCallCount++;
           return itemLoaderResults.removeAt(0).call(limit, start: start);
         },
@@ -326,18 +304,18 @@ void main() {
     testWidgets('retry from subsequent failure (critical)', (tester) async {
       var itemLoaderCallCount = 0;
       final itemLoaderResults = [
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           return List.generate(15, (i) => i);
         },
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           throw InfiniteListException();
         },
-        (int limit, {int start}) async {
-          return List.generate(15, (i) => i + start);
+        (int limit, {int? start}) async {
+          return List.generate(15, (i) => i + start!);
         },
       ];
       await tester.pumpApp(InfiniteList<int>(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           itemLoaderCallCount++;
           return itemLoaderResults.removeAt(0).call(limit, start: start);
         },
@@ -384,18 +362,18 @@ void main() {
     testWidgets('retry from subsequent failure', (tester) async {
       var itemLoaderCallCount = 0;
       final itemLoaderResults = [
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           return List.generate(15, (i) => i);
         },
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           throw Exception('oops');
         },
-        (int limit, {int start}) async {
-          return List.generate(15, (i) => i + start);
+        (int limit, {int? start}) async {
+          return List.generate(15, (i) => i + start!);
         },
       ];
       await tester.pumpApp(InfiniteList<int>(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           itemLoaderCallCount++;
           return itemLoaderResults.removeAt(0).call(limit, start: start);
         },
@@ -443,13 +421,13 @@ void main() {
         (tester) async {
       var itemLoaderCallCount = 0;
       final itemLoaderResults = [
-        (int limit, {int start}) async {
+        (int limit, {int? start}) async {
           return List.generate(15, (i) => i);
         },
-        (int limit, {int start}) async => <int>[],
+        (int limit, {int? start}) async => <int>[],
       ];
       await tester.pumpApp(InfiniteList<int>(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           itemLoaderCallCount++;
           return itemLoaderResults.removeAt(0).call(limit, start: start);
         },
@@ -494,7 +472,7 @@ void main() {
 
     testWidgets('renders default empty widget by default', (tester) async {
       await tester.pumpApp(InfiniteList(
-        itemLoader: (int limit, {int start}) async => [],
+        itemLoader: (int limit, {int? start}) async => [],
         builder: InfiniteListBuilder(success: (_, __) => const SizedBox()),
       ));
 
@@ -505,7 +483,7 @@ void main() {
     testWidgets('renders default error widget by default (generic)',
         (tester) async {
       await tester.pumpApp(InfiniteList(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           throw Exception('oops');
         },
         builder: InfiniteListBuilder(success: (_, __) => const SizedBox()),
@@ -518,7 +496,7 @@ void main() {
     testWidgets('renders default error widget by default (specific)',
         (tester) async {
       await tester.pumpApp(InfiniteList(
-        itemLoader: (int limit, {int start}) async {
+        itemLoader: (int limit, {int? start}) async {
           throw InfiniteListException();
         },
         builder: InfiniteListBuilder(success: (_, __) => const SizedBox()),